Selecting Horse Hay: Separating Fact From Fiction

Proper round bale storage, handling, and feeding will minimize the risk of botulism infection in horses.

Photo: Jimmy Henning, PhD

Horse people are often described as picky, fussy, or difficult when it comes to hay selection. This is not surprising since most horses are either very valuable or viewed as part of the family.

But it’s often a lack of knowledge about selecting quality hay that gives horse owners a bad name and forces them to pay more for hay than their neighbors with other types of livestock. Myths develop because of a piece of truth that becomes inflated and held as absolute truth without justification. To improve our knowledge of hay selection, here are a few common myths about hay, how these myths came to be accepted, and, finally, the truth.

(Note: For the purposes of this article, “high-quality hay” refers to hay with a high nutritive value).

Myth: Second-cutting hay is always the best cutting.

How it came about: The No. 1 factor that determines hay quality is stage of maturity at harvest. Cool-season grasses such as orchardgrass and timothy will produce a seedhead in the spring, often just in time for the first cutting. For the hay producer, this means an increase in yield and, therefore, more bales to harvest and sell. However, this also means that the crop’s fiber is elevated and quality is reduced. Because cool-season grasses only produce seedheads once per year, subsequent cuttings are seedhead-free and generally less fibrous. Additionally, second-cuttings tend to cure quicker and are less likely to experience rain damage; both factors contribute to higher quality relative to first-cutting.

Truth: First-cutting hay can be high-quality if cut early. Stage of maturity and other management factors affect hay quality at harvest. High-quality (or low-quality) hay can be harvested from late spring to late fall if weather and management conditions are right. Never assess quality based on cutting number. Rather, have a laboratory perform a hay analysis to determine quality.

Myth: Horses require higher-quality hay than cattle.

How it came about: In general, horses do require higher-quality hay than cattle because their digestive tracts are very different. Cattle are ruminants and able to breakdown fiber very efficiently, whereas horses are monogastrics with a functional cecum (or so-called hindgut fermenters) and are less efficient at fiber digestion. Therefore, cattle can maintain weight well on hay that horses cannot digest well.

Truth: Individual needs of the animal should dictate the quality of hay provided. An easy-keeping Quarter Horse in light work does not need the same quality of hay as a Thoroughbred at the peak of his racing career. Similarly, an open Angus cow doesn’t require the same quality hay as a high-producing dairy Holstein needs at the peak of lactation. Consider your horse’s current body condition, level of work, and pasture availability, then choose hay that will meet, but not exceed, his needs based on hay test results.

Myth: __________ is the best hay variety.

How it came about: Such statements often come from horse owners that have moved from one area of the country (or world) to another and are not accustomed to the local hay. Forage species used for hay fall into one of two categories: grasses (such as orchardgrass, Kentucky bluegrass, tall fescue, bermudagrass, timothy, teff, and smooth bromegrass) and legumes (including alfalfa, red and white clover, lespedeza, and birdsfoot trefoil).

Truth: Hay quality is dependent on the forage species or variety. When managed and harvested correctly, legumes are naturally higher in quality than grasses; however, there is little difference between different types of grasses and legumes when all other factors are held constant. Buying quality, local hay will likely save money due to reduced transportation costs. Be sure to address any concerns with a specific grass or legume species, such as endophyte-infected tall fescue for broodmares, with your hay producer. If you are concerned about feeding a certain species of hay, consult your local county extension agent or equine nutritionist.

Myth: Round bales and/or silage contain diseases, such as botulism, and should not be fed to horses.

How it came about: Botulism’s causative bacterium prefers moist conditions and is commonly found in the soil, stream sediments, and intestinal tracts of fish and mammals. Silage (fed more commonly outside the United States) is stored with higher moisture than hay and, when not properly handled, can allow the bacteria to flourish. Round bales are often baled at a similar moisture content as small square bales, but are more likely to be stored outside without cover from rain. This wet environment encourages bacteria growth.

Truth: Proper round bale storage, handling, and feeding will minimize the risk of botulism infection in horses. Round bales should be covered when stored and fed using a hay feeder to reduce contamination from trampling and urination. Do not feed round bales that show clear signs of mold to horses. Silage should be put up at the proper moisture content for the style of storage, kept airtight until feeding, and fed quickly to reduce botulism risk. Always test silage quality before feeding. Finally, discuss a botulism vaccine with your veterinarian if your horse resides in a botulism-prone area.

Myth: Don’t feed hay that has been rained on.

How it came about: Rain negatively affects hay in a variety of ways:

  • Rain on recently cut hay can prolong plant respiration and reduce energy content;

  • Rain on legumes will cause leaves to separate from the stems (called leaf shatter) and, therefore, remove the more nutritious portion of the plant. This means the final product will contain more fibrous stems, which reduces the quality;

  • Rain causes sugar and other carbohydrates, proteins, and minerals to leach from hay; and

  • Heavy rain can splash soil up onto curing hay, which can increase dustiness and rapidity of molding.

Test hay once it’s been stored for six to eight weeks—this will provide the most accurate results.

Photo: University of Kentucky’s College of Agriculture, Food, and Environment

Truth: Rained-on hay can be acceptable quality. While rain usually negatively affects hay, to what degree depends on several factors, including what type of hay is being harvested, how much rain fell and how intensely, stage of curing when it rained, and what the producer does to counteract these negative effects. For example, if rain occurs within a day of cutting, it has very little effect on hay quality. All hay, especially material that has been rained on, should be tested for quality and inspected for mold or dustiness before use.

Myth: Hay should be stored for six weeks before feeding.

How it came about: This myth likely came about from hay testing. After hay is stored in a barn, it will continue to cure for four to eight weeks. This means that the quality of the hay can change slightly over time before it becomes stable.

Truth: Hay can be fed at any time after harvesting. Do not test hay until it has been stored for six to eight weeks—this will provide the most accurate results. While feeding hay sooner will not be harmful to horses, it can be difficult to balance the ration because the hay quality is unknown.

Myth: Green is good; brown is bad.

How it came about: Often, hay harvested too late or mishandled will lose its green color due to processes such as heating and bleaching. Green hay is less likely to have gone through these processes and more likely to be a better-quality.

Truth: A hay test is the only way to truly evaluate quality. No quality factors directly affect color or vice versa. Therefore, color is an inconsistent means by which to evaluate hay quality.

Myth: Feeding hay causes a large distended digestive tract, known as a hay belly.

How it came about: A hay belly usually results when malnourished horses receive large quantities of low-quality, high-fiber hay. These horses are usually be thin over the neck, withers, ribs, and hindquarters, while the belly appears large because they’re consuming large amounts of hay.

Truth: A balanced ration that includes quality pasture or hay will maintain a horse at an ideal condition without excessive gut fill.

Take-Home Message

Horses evolved consuming forage, and, whether in the form of pasture or hay, it remains an important component of the equine diet. The ideal hay for your horse will depend on his current condition, work level, pasture availability, and the management logistics on your farm. Always inspect hay to ensure it’s free from contaminates such as weeds, insects, mold, dust, and other foreign material. Also, evaluate hay’s nutritional value prior to feeding so you can formulate and balance a ration to meet your horse’s particular needs.

For more information, see the following University of Kentucky (UK) publications at

Krista Lea, MS, UK Horse Pasture Evaluation coordinator; Ray Smith, PhD, forage extension specialist; Tom Keene, MS, hay marketing specialist; Chris Teutsch, PhD, forage extension specialist; and Jimmy Henning, PhD, provided this information.

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More information on Gluck Equine Research Center and UK Ag Equine Programs.